Large intestine Structure and FUnction Flashcards
illium - caecum valve name?
Ileo-cecal valve
Vremiform is what?
appendix
length of colon
1.5-1.8m
Does the large intestine have villi? Why?
No, flat surface to move dehydrating poop out easier
Does the large intestine have crypts/goblet cells?
Yes
Why does the large intestine need a large amount of goblet cells?
High amounts of lubrication are needed
Rectum mucosa? What is the muscularis externa like in the rectum?
Simpole columnar epithelium. Thick muscularis externa compared to other GI regions
What is the thickenin of the muscularis of anal canal called? What other muscle is there?
Internal (smooth muscle) anal sphincter.
Also has external anal sphincter which is skeletal muscle (we control woo)
What is the transition of epithelium in the anal canal?
simple columnar to stratified squamous
How does the colon resorbed water?
THrough sodium resorption (initialted by the NaKATPase pump which osmotically brings water in
Why do we want a long residensce time in colon? How many bact? What foes bacerial fermentation do?
Time for bact to act!
10^14 (1kg)
Ferments undigested carbs (cellulose) to short chain fatty acid.
Produces Vit K
What key ntrient do the bact. of our larg intestine produce? What do we do for babies?
Vit K
Give babies an injection
What gasses do we fart? CAused by what?
Methane, Nitrogen, CO2, Hydrogen, Hydrogen Sulphide
Which anal sphincter do we have control over?
The external one
What is the defaecation reflex? WHat is it stimulated by?
Our urge to poop.
Caused by mechanoreceptors in rectum sensing distension, and stimulated by increased peristaltic activity in the colon.
What type of peristalis do we get following a meal?
Mass movement contraction (intense peristalsis) colon - rectum
What controls the defaecation reflex?
Parasympathetic control – via pelvic splanchnic nerves (no sympathetic influence)
What symptoms are associated with a constipation?
Headache, Nausea, loss of appitite, abdominal distension
WHat is diarrhoea? WHat are the issues? WHat are the causes?
too runny and too frequent diahorrea
Dehydration is main issue
Can be caused by bact, vius, toxins, foodm stress, protozoa
Vibrio Cholerae, E.Coli both produce what? WHat effect does this have?
Enterotoxigenic Bacteria
(So they both produce enterotoxins, which maximally turn on Cl secretion from crypt cells into the lumen)
Brings in a shed tonne of water
Which intracellular second messengers will be elevated by exnterotoxigenic batheria?
cAMP, cGMP and calcium
How is secretory Diarrhoea treated?
Oral rehydration treatment
Salt and Glucose, drives H20 reabsorption
